In various kinds of applications such as a hybrid automobile and an electric automobile, there is utilized an electric power converter that can bidirectionally transmit electric power in such a way as to perform power-running operation for converting DC-electric-power voltage inputted from a DC power source such as a battery so as to supply the voltage to a motor and in such a way as to perform regenerative operation for supplying DC electric power generated by the motor to the DC power source. The output voltage, which is outputted from the electric power converter to the motor, fluctuates due to various factors such as fluctuation of a target voltage, load fluctuation of the motor, and a dead time. With regard to these fluctuations of the output voltage, there has been disclosed (e.g., refer to PTL 1) a control apparatus for a boosting converter that adjusts the gain in feedback control and feed-forward control of the output voltage, based on the difference between the target voltage and the output voltage and the changing rate of the target voltage.